Renesas Electronics ISL78714 battery management IC

Renesas Electronics’ fourth-generation lithium-ion battery management IC, the ISL78714, provides cell voltage and temperature monitoring along with cell balancing and extensive system diagnostics to protect 14-cell Li-ion battery packs while maximising driving time and range for hybrid and electric vehicles (HEV/MHEV/PHEV/BEV). It offers a combination of battery pack monitoring, fast data acquisition and fault checking features.

The feature-rich device monitors and balances up to 14 series connected cells with ±2 mV accuracy across automotive temperature ranges, letting system designers make informed decisions based on absolute voltage levels. It includes a precision 14-bit analog-to-digital converter and associated data acquisition circuitry. The device also offers up to six external temperature inputs (two available from GPIOs) and includes fault detection and diagnostics for all key internal functions.

The product is designed to meet the stringent performance requirements of battery pack systems for all EV variants, including HEV/PHEV, with safety features enabling automotive manufacturers to achieve the ISO 26262 automotive safety integrity level (ASIL D). In addition, it monitors and reads back over/undervoltage, temperature, open wire conditions and fault status for 112 cells in less than 10 ms, or 70 cells in 6.5 ms.

Multiple devices can be connected together via a daisy chain that supports systems up to 420 cells (30 ICs) that provide transient and EMC/EMI immunity, said to exceed automotive requirements. The daisy-chain architecture uses capacitive or transformer isolation, or a combination of both, with twisted pair wiring to stack multiple battery packs together while protecting against hot plug and high voltage transients. A watchdog timer automatically shuts down a daisy-chained IC if communication is lost with the master MCU.